Are your Pekins male or female. If they are both female, this is possible (with the extra work KathiQuacks mentioned). But, if you have a pair, it is unlikely to work. They will see the new duck as an intruder to be driven off.
I had a single drake duckling 2 summers ago (only one hatched). I did as mentioned and raised him with mirrors, stuffed animals, brought him to work with me, and we visited my “big ducks” frequently. He then slowly joined them when he was 3-4 months old. He is head drake (he has a son now) of my current flock of 8. He is also very sweet to the girls as they taught him when he was young how to act. So, yes, it is possible but it isn’t easy.